1. Field of the invention
The present invention relates to a free access type floor, in which a secondary floor forming a wiring or air conditioning duct chamber or the like is formed, and a method of installing the same, in particular as a free access type floor, in which a plurality of floor boards are arranged in a closely connected manner on a single plane to form a secondary floor, for use in an electronic computer room, wherein wiring cables or codes and the like are disposed, or an office, wherein various kinds of office apparatus are arranged, and a method of installing the same. The present invention relates also to a free access type floor having a construction in which a plurality of floor board layers are engaged with a support member separately and independently.
2. Description of the prior art
Installation of office apparatus and communication apparatus in offices has increased with the development of office automation. Accordingly, wires and pipes must be installed. In order to simplify such construction, secondary floors have been constructed at a given height above the primary floor. Free access type floors comprising floor panels for forming a secondary floor on the primary floor and a support member for supporting said floor panels on the primary floor in a closely connected manner can be classified into those in which floor boards and the support member are separately formed, and those in which the floor boards and the support member are integrally formed.
The latter, as shown in FIG. 77, are provided with support members b mounted on each of the corner portions of the lower surface of a floor panel a, the secondary floor being formed by laying said support members b on the primary floor.
With such free access type floors, in which the floor panel and the support members are integrally formed, all floor panels are laid, and subsequently, the panels required for wiring must be removed. If the wiring density is high, there is the possibility that some wires are forced under the support members, leading to electrical troubles after the floor panels are laid upon the completion of the wiring.
The former, as shown in FIG. 78, are provided with a plurality of support members c, which are provided with engaging portions d in the upper portion thereof, mounted on the appointed positions of the primary floor with adhesives or anchor bolts, floor boards e being laid on the support members c by inserting the engaging portions d of the support members c into engaging holes f of the floor board e to form a double floor. With such a free access type floor, in which floor boards and support members are separately formed, it is indispensable to carefully determine the positions of the support members on the primary floor. After the positions of the support members to be installed are determined, the support members must be mounted on the floor with adhesives or the like. Since the support members are mounted on the floor, damage to the primary floor is inevitable.
Also, there are floors in which a runner comprising a positioning sheet or the like is arranged on the primary floor in combination with a pedestal, floor boards being laid on the pedestal, and each floor board being mounted by means of a locking means. With such free access type floors, the position of the pedestal sometimes shifts from the appointed position on the floor due to production tolerance. Hence superiority in construction and a precise finished size cannot be achieved. Also, fasteners cannot securely fix the floor boards to each other, so that the floor boards are apt to shift. Besides, since a runner is used, the material and construction costs are high.
In addition, floors, in which adjacent corner portions of floor boards are arranged on a single bolt, which is mounted on the floor in a closely connected manner, have been developed. In this case, a support plate is placed between two nuts screwed onto the bolt. The corner portions of each floor board are placed on said support plate. In this case, adjustment of the height of the corners can be simultaneously carried out for all floor boards. But, the adjustment of the height of the floor boards must be carried out by rotating the nuts before the floor boards are placed on the support plate. Accordingly, it is necessary to remove the floor board in order to adjust its height at a later date. In addition, since the corner portions of the adjacent floor boards must be simultaneously adjusted in height, minute regulation of each floor board in height can not be carried out, if the floor boards are different in thickness from each other. Since the support plate for supporting the floor board is mounted by means of the nuts, the nuts are apt to become loose by vibration due to travel on the floor boards. There is, therefore, the possibility that the height of the floor boards will change with use. In addition, there is the possibility that floor boards will become damaged at portions where the support plates are in contact with the floor board.
In order to eliminate this problem, the threaded portion of the bolt can be covered with an adhesive after the adjustment of the height of the floor board. However, if floor boards are replaced due to the breakage or the like, and if the floor boards are different in thickness from each other, the height cannot be adjusted thereby making it difficult to maintain an equal height over the total floor surface.
Another method, in which a bolt is fastened at the side by means of a locking bolt after the adjustment of the height of the floor board, has been proposed. However, the locking bolt itself can become loose due to vibrations of the floor board, so that the bolt cannot be securely fixed. In addition, there is the possibility that travel on the upper surface of the floor board will lead to the generation of noise resulting from contact with the adjacent floor boards and the contact of the floor board with the shores. In order to prevent such noise, adjacent floor boards or the floor board and the shores have been provided with a soundproofing material such as rubber sheet. However, in the case where the adjacent floor boards or the floor board and the shores are provided with soundproofing material at only any one of the facing portions thereof, sufficient soundproofing cannot be achieved. In addition, in the case where the soundproofing material is inserted between the floor boards, said soundproofing material is often caught on the floor boards and as a result, engagement of the floor boards with each other becomes difficult, whereby it is difficult to arrange the floor boards in a closely connected manner to form a single plane.
In each of the above-mentioned cases, the secondary floor is constructed on one plane over the primary floor and the wiring space, defined by the secondary floor adn the primary floor, and is not divided into a separate space for electric power cables and signal cables. Accordingly, wires for electric power have an electro-magnetic influence upon signal wires leading to the modulation of signals to and from the office apparatus. In order to avoid such a phenomenon, a floor material, in which this wiring space can be divided into two layers by a cable-housing separator, has been proposed. In this floor, since said cable-housing separator and floor boards are engaged with each other by means of uneven engaging members and are integrally supported on the floor by means of supporting members, adjustment of the space formed by the separator is almost impossible. Accordingly, the wires cannot be housed in the appointed space when the quantity of wires becomes large. In addition, the engagement of the floor boards with the separator is insufficient, so that there is the possibility that the floor panels become separated from the engaging members due to vibrations of the floor and the like. Furthermore, known separators are not provided witha drainage mechanism, which leads to possible damage when liquids are spilled on the secondary floor and accumulate in the separator area.